US4566975A - Method for purifying aqueous solutions - Google Patents
Method for purifying aqueous solutions Download PDFInfo
- Publication number
- US4566975A US4566975A US06/649,712 US64971284A US4566975A US 4566975 A US4566975 A US 4566975A US 64971284 A US64971284 A US 64971284A US 4566975 A US4566975 A US 4566975A
- Authority
- US
- United States
- Prior art keywords
- stage
- aqueous solution
- precipitating
- precipitate
- precipitation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/103—Arsenic compounds
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/105—Phosphorus compounds
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/20—Heavy metals or heavy metal compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/06—Controlling or monitoring parameters in water treatment pH
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S210/00—Liquid purification or separation
- Y10S210/902—Materials removed
- Y10S210/906—Phosphorus containing
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S210/00—Liquid purification or separation
- Y10S210/902—Materials removed
- Y10S210/911—Cumulative poison
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S210/00—Liquid purification or separation
- Y10S210/902—Materials removed
- Y10S210/911—Cumulative poison
- Y10S210/912—Heavy metal
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S210/00—Liquid purification or separation
- Y10S210/902—Materials removed
- Y10S210/911—Cumulative poison
- Y10S210/912—Heavy metal
- Y10S210/914—Mercury
Definitions
- the present invention relates to a method for purifying aqueous solutions containing at least one impurity element from the group consisting of arsenic, phosphorus, mercury and other heavy metals and solid matter. More specifically, the invention relates to a method for removing impurities by precipitation in at least two stages in an acid-free environment with the aid of known precipitation reagents possessing ions capable of forming hydroxide precipitates.
- arsenic can be isolated from aqueous solutions by precipitation with the aid of the system Me n+ /Me(OH) n , i.e. a combination of free ions and hydroxide of the element Me.
- Me n+ /Me(OH) n i.e. a combination of free ions and hydroxide of the element Me.
- Mn, Zn, Cd, Cr, Fe, Al and Ca Of these elements, Fe, Al and Ca are considered the most suitable for use in the present context, since they do not create environmental problems of an unduly serious nature.
- the precipitation reagent When separating the impurities by precipitation in accordance with known methods, however, the precipitation reagent must be used in a quantity which ensures a substantial stoichiometric excess of precipitation-ions.
- the reason herefor is thought to be because a percentage of the precipitation-ions introduced form complexes in the solution and thereby become inactive.
- many of the ions in question e.g. Al and Fe, are liable to build complexes in aqueous solutions, in the presence of sulphur dioxide, to form sulphur/oxy-compounds.
- phosphorous is precipitated from the aqueous solution with the aid of lime in a single stage, and part of the slime formed during this precipitation process is returned to the process, to be mixed with the precipitation reagent as it is charged to the aqueous solution.
- the best reagents for use in this connection are iron and aluminium ions, although other metal ions, such as Mn, Zn, Cd and Cr, can also be used.
- metal ions such as Mn, Zn, Cd and Cr
- magnesium and/or calcium compounds it is also possible in certain instances to use magnesium and/or calcium compounds.
- the hydroxide solubility of the metals in group 2a of the periodic system is high, they can still be used as a precipitation reagent in concentrated solutions containing large quantities of impurities.
- the group 2a metals are highly attractive sources of hydroxide, and hence they can be used in spite of their aforementioned drawbacks.
- the impurities in question are precipitated in two or more stages, in which a large percentage of the precipitation reagent is supplied in the second stage and also to any subsequent stage.
- a hydroxide precipitate which contains the impurities and which can be substantially completely separated from the solution. No harm is caused if a minor part of the aqueous solution accompanies the precipitate when it is separated from the solution, provided that substantially all of the precipitate is removed from the remainder of the solution.
- the aqueous solution from which the precipitate has been removed can be safely dumped, while the precipitate itself, together with any accompanying solution, can be returned to the water.
- the procedure adopted when returning the precipitate can take many forms, the important thing being that the precipitate is present in the first precipitation stage.
- the precipitate can be returned to the impure aqueous solution introduced to the first precipitation stage, optionally subsequent to alkalizing the precipitate if necessary, or alternatively, if found more practical, the precipitate can be returned directly to the first precipitation stage.
- the precipitate may first be dissolved in water before being returned to the aqueous solution before or in the first precipitation stage.
- the precipitate present in the aqueous solution subsequent to the first precipitation stage is removed from said stage in the form of a mud or sludge, prior to introducing the aqueous solution to the second precipitation stage.
- the quantity of precipitation agent supplied to the various stages is adapted so that the ratio of the amount of precipitation ions present in the solution to the amount of impurity element ions contained therein is much lower than in subsequent stages. More specifically, it should be ensured that the quantity of precipitation reagent supplied to the first stage is such that the ratio of equivalents of precipitation metal-ions to moles of impurity elements is at least 0.8, preferably between 1 and 3, said ratio being expressed hereinafter as X. In the last stage the ratio X is suitably at least 2, preferably between 10 and 15.
- the precipitation reagent introduced can be divided between the second stage and any subsequent stage or stages, although it is preferably introduced to the last stage, so as to obtain the aforementioned ratio X in the final stage of the process.
- the solution should be alkaline or should at least have a pH at which hydroxide precipitations are formed. Consequently, it may be necessary to add alkali, suitably Ca(OH) 2 , NaOH or NH 4 OH, prior to the first precipitation stage. In this respect, it has been found advantageous to maintain a pH in the solution of at least about 9 when precipitating Me(OH) 2 -impurity element in the first stage. In the second stage, or any subsequent stage, a pH of between 8 and 9 is sufficient to achieve acceptable precipitation. The pH can be lower when using other hydroxide builders, such as Me 3+ -ions.
- Sludge present in the solution subsequent to the first stage is suitably separated from said solution mechanically, preferably by centrifugation, there being obtained in this way an extremely thick sludge. It is not absolutely necessary for all of the sludge to be removed at this stage, since any remaining sludge will be isolated and removed after the final stage, and returned to the process.
- Precipitation is best carried out at solution temperatures beneath about 50° C., and preferably beneath 30° C.
- FIGURE is a flow sheet illustrating a preferred embodiment of the invention, and also with reference to a number of practical working examples.
- a contaminated solution is charged to a mixing tank 10, to which alkali and optionally also return sludge are also charged.
- Alkali is charged to the tank 10, to adjust the pH of the solution to about 9.0.
- the thus alkalised solution is pumped through a pipe 11 to a first precipitation tank 12.
- FeSO 4 is added to the solution in the tank 12, to which sludge containing impurities and iron separated from a subsequent precipitation stage, is also charged through a pipe 13.
- Iron sulphate is added solely in an amount which provides a total ratio X of at least 1-3. In this way, between 70 and 80% of the impurity content of the solution is precipitated out.
- Solution and precipitate are removed from the tank 12 through a pipe 14, and passed to a separation plant 15, which suitably comprises a separator. At least a substantial part of the precipitate present is separated from the solution in the separator 15. As previously indicated, it is not necessary to attempt to remove all the precipitate at this stage.
- the impurity-containing sludge separated from the solution is removed for further processing with respect to its content of impurity and precipitating agent metals.
- the solution freed from the major part of its impurity content in the separator 15 is then pumped to a further precipitation tank 17.
- Alkali here exemplified as NaOH
- a precipitation agent here exemplified as FeSO 4 .
- the amount of alkali added to the solution is adapted so that, subsequent to adding FeSO 4 , the pH of said solution lies within the range of 8.0-9.0, while the amount of sulphate added is adapted so that the ratio X in the solution lies between 10 and 15. In this way, impurity elements can be precipitated-out to a residual content of less than 1 mg/l solution.
- the majority of the precipitate formed often comprises a relatively voluminous iron-hydroxide with impurity ions such as AsO 2 - adsorbed thereon. Any mercury and other heavy metals present in the solution will thus be precipitated out, together with any arsenic and phosphorous and the iron, to leave extremely low residual contents.
- iron sulphate as the precipitation agent, it has, for example, been found possible to precipitate mercury to residual contents beneath about 10 -3 mg/l, as compared with the relatively high residual contents of from 10 -1 -10 -3 mg/l achievable with hitherto known methods.
- the solution and the precipitate present therein is passed through a pipe 18 to a flocculating tank 20, to which a suitable flocculating agent is passed through a supply pipe 19.
- the thus treated solution is pumped from the flocculating tank 20 through a pipe 21 to a lamella separator 22.
- the flocculated precipitate is separated from the solution in the lamella separator, and is removed in the form of a sludge from the bottom of the separator 22, as indicated by the line 23, while cleansed solution is removed via an overflow pipe 24, and passed to a cloth filter 25, where the solution is cleansed still further and from which the filtered, purified solution is withdrawn and dumped.
- the sludge taken from the bottom of the lamella separator 22 is passed through the pipe 23 and the pipe 13 back to the first precipitation tank 12, or through the pipe 13 A shown in broken lines and back to the mixing tank 10.
- the sludge can be charged to the ingoing solution and mixed therewith, prior to charging the solution to the mixing tank 10.
- Those impurity-element containing aqueous solutions which can be advantageously purified by means of the method according to the invention include acid condensate containing arsenic, mercury, selenium, cadmium and any other heavy metals and any solid matter formed when cooling roaster gases in accordance with the roaster-gas cleansing method described in U.S. Pat. No. 4,138,231 assigned to Boliden Aktiebolag.
- the invention can advantageously be generally employed for the purification of process water solutions derived from chemical and metallurgical industries, especially solutions containing arsenic and heavy metals.
- the condensate had a pH of 0.5-1.5.
- the pH was adjusted to about 9 by adding 25% NaOH.
- Oxidic iron-arsenic sludge was charged to step 1 and FeSO 4 was charged to stage 2.
- the FeSO 4 charged to stage 2 was in the form of a non-acid solution having a pH of 8-9.
- the iron was charged in an amount such that the weight ratio Fe/As in the first stage was about 0.5 and in the second stage about 7.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Hydrology & Water Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- Inorganic Chemistry (AREA)
- Removal Of Specific Substances (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Detergent Compositions (AREA)
- Treatment Of Sludge (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE8304858A SE452307B (sv) | 1983-09-12 | 1983-09-12 | Forfarande for rening av fororenade vattenlosningar innehallande arsenik och/eller fosfor |
SE8304858 | 1983-09-12 |
Publications (1)
Publication Number | Publication Date |
---|---|
US4566975A true US4566975A (en) | 1986-01-28 |
Family
ID=20352439
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US06/649,712 Expired - Lifetime US4566975A (en) | 1983-09-12 | 1984-09-12 | Method for purifying aqueous solutions |
Country Status (15)
Country | Link |
---|---|
US (1) | US4566975A (el) |
EP (1) | EP0139622B1 (el) |
JP (1) | JPS60143893A (el) |
AT (1) | ATE31289T1 (el) |
BR (1) | BR8404502A (el) |
CA (1) | CA1253981A (el) |
DE (1) | DE3468010D1 (el) |
ES (1) | ES535544A0 (el) |
GR (1) | GR80306B (el) |
MA (1) | MA20224A1 (el) |
MX (1) | MX7707E (el) |
PT (1) | PT79186B (el) |
SE (1) | SE452307B (el) |
YU (1) | YU43855B (el) |
ZA (1) | ZA846790B (el) |
Cited By (57)
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US4717484A (en) * | 1985-03-06 | 1988-01-05 | Kaeuffer Karl C | Process for completing circulatory systems used to purify water and sewage |
WO1988010243A1 (en) * | 1987-06-18 | 1988-12-29 | Bethlehem Steel Corporation | Process for chemical stabilization of heavy metal bearing dusts and sludges, such as eaf dust |
US4814091A (en) * | 1987-06-29 | 1989-03-21 | The United States Of America As Represented By The United States Department Of Energy | Process for removing metals from water |
US4840671A (en) * | 1987-06-18 | 1989-06-20 | Bethlehem Steel Corporation | Process for chemical stabilization of heavy metal bearing dusts and sludges as EAF dust |
EP0364423A1 (en) * | 1988-10-11 | 1990-04-18 | Boliden Contech Ab | A method for purifying contaminated aqueous solutions |
US4940549A (en) * | 1989-01-31 | 1990-07-10 | Santina Water Company | Method for removing toxic metals from agricultural drain water |
US5039428A (en) * | 1990-03-05 | 1991-08-13 | Tetra Technologies, Inc. | Waste water treatment process using improved recycle of high density sludge |
US5093007A (en) * | 1989-05-24 | 1992-03-03 | Nerco Minerals Company | Process for removal of inorganic and cyanide contaminants from wastewater |
US5114592A (en) * | 1989-03-31 | 1992-05-19 | Walhalla-Kalk, Entwichlungs- Und Vertriebsgesellschaft Mbh | Procedure for separating arsenic from waste material |
US5128047A (en) * | 1990-04-20 | 1992-07-07 | Rhone-Poulenc Inc. | Sequential separation of metals by controlled pH precipitation |
US5200087A (en) * | 1990-12-12 | 1993-04-06 | Kubota Corporation | Method of and apparatus for recovering mercury from drainage |
US5200082A (en) * | 1991-07-02 | 1993-04-06 | Santina Water Company | Method for removing toxic substances from industrial and agricultural waste water |
US5252003A (en) * | 1990-10-29 | 1993-10-12 | International Technology Corporation | Attenuation of arsenic leaching from particulate material |
US5259697A (en) * | 1987-06-18 | 1993-11-09 | Bethlehem Steel Corporation | Composition and process for forming low permeability barriers for waste disposal sites |
US5262063A (en) * | 1992-05-14 | 1993-11-16 | Elf Atochem North America, Inc. | Multiple-stage precipitation process for heavy metals in aqueous solution |
US5348662A (en) * | 1992-05-14 | 1994-09-20 | Elf Atochem North America, Inc. | Process for removing heavy metals from aqueous solutions |
US5368703A (en) * | 1992-05-12 | 1994-11-29 | Anco Environmental Processes, Inc. | Method for arsenic removal from wastewater |
US5443622A (en) * | 1994-02-28 | 1995-08-22 | Kennecott Corporation | Hydrometallurgical processing of impurity streams generated during the pyrometallurgy of copper |
US5543049A (en) * | 1991-02-04 | 1996-08-06 | Delman R. Hogen | Microbial mediated water treatment |
US5545331A (en) * | 1991-04-08 | 1996-08-13 | Romar Technologies, Inc. | Recycle process for removing dissolved heavy metals from water with iron particles |
US5616168A (en) * | 1994-02-28 | 1997-04-01 | Kennecott Utah Copper Corporation | Hydrometallurgical processing of impurity streams generated during the pyrometallurgy of copper |
US5618439A (en) * | 1993-04-20 | 1997-04-08 | Boliden Contech Ab | Method for purifying industrial sewage water |
US5620893A (en) * | 1992-07-16 | 1997-04-15 | Delman R. Hogen | Microbial mediated method for soil and water treatment |
US5720882A (en) * | 1993-08-26 | 1998-02-24 | Kemira Kemi Ab | Treatment method for waste water sludge comprising phoshorous, heavy metals and at least one metal |
US5728295A (en) * | 1996-04-19 | 1998-03-17 | Fuji Hunt Photographic Chemicals, Inc. | Apparatus for removing metal ions and/or complexes containing metal ions from a solution |
US5762891A (en) * | 1996-02-27 | 1998-06-09 | Hazen Research, Inc. | Process for stabilization of arsenic |
US5840194A (en) * | 1996-01-16 | 1998-11-24 | Mitsubishi Jukogyo Kabushiki Kaisha | Process for treating arsenic-containing waste water |
US5976383A (en) * | 1991-04-08 | 1999-11-02 | Romar Technologies, Inc. | Recycle process for removing dissolved heavy metals from water with aluminum particles |
US6042721A (en) * | 1997-07-23 | 2000-03-28 | Fabco Industries, Inc. | Effluent treatment apparatus |
US6117333A (en) * | 1997-04-22 | 2000-09-12 | Union Oil Company Of California | Removal of hydrocarbons, mercury and arsenic from oil-field produced water |
US6177015B1 (en) * | 1999-10-18 | 2001-01-23 | Inco Limited | Process for reducing the concentration of dissolved metals and metalloids in an aqueous solution |
US6251283B1 (en) * | 1999-09-03 | 2001-06-26 | Perma-Fix Environmental Services, Inc. | Methods for removing selenium from a waste stream |
US6254783B1 (en) | 1996-03-11 | 2001-07-03 | Stephen R. Wurzburger | Treatment of contaminated waste water |
WO2001062360A2 (en) * | 2000-02-25 | 2001-08-30 | Watermark Technologies, Llc | Methods and apparatus for pressure stabilized removal of contaminants from solution |
US6319482B1 (en) | 1996-05-20 | 2001-11-20 | Apex Residue Recovery Inc. | Treatment of fly ASH/APC residues including lead salt recovery |
US6387276B1 (en) * | 1997-06-19 | 2002-05-14 | The University Of Connecticut | Immobilization of inorganic arsenic species using iron |
WO2002048046A2 (en) | 2000-12-14 | 2002-06-20 | Barrick Gold Corporation | Process for recovering arsenic from acidic aqueous solution |
US20040146993A1 (en) * | 2002-11-13 | 2004-07-29 | Khare Anil B. | Isolating chondroitin sulfate |
US20040222162A1 (en) * | 2003-05-07 | 2004-11-11 | Industrial Technology Research Institute | Method of arsenic immobilization in crystalline form from water |
US6821434B1 (en) | 2001-10-10 | 2004-11-23 | Sandia Corporation | System for removal of arsenic from water |
US20070090057A1 (en) * | 2005-09-13 | 2007-04-26 | John Burckle | Process for the purification of acidic metal-bearing waste waters to permissable discharge levels with recovery of marketable metal products |
US7247242B1 (en) | 2001-10-10 | 2007-07-24 | Sandia Corporation | Arsenic removal from water |
US20070209989A1 (en) * | 2004-04-26 | 2007-09-13 | Mitsubishi Materials Corporation | Reducing water purification material, method for producing reducing water purification material, method for treating wastewater, and wastewater treatment apparatus |
US20080093580A1 (en) * | 2003-01-29 | 2008-04-24 | Union Oil Company Of California Dba Unocal | Composition for removing arsenic from aqueous streams |
US20080156734A1 (en) * | 2006-12-28 | 2008-07-03 | Chevron U.S.A. Inc. | Apparatus for treating a flow of an aqueous solution containing arsenic |
US20090107919A1 (en) * | 2007-10-31 | 2009-04-30 | Chevron U.S.A. Inc. | Apparatus and process for treating an aqueous solution containing chemical contaminants |
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Families Citing this family (3)
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US4724084A (en) * | 1986-03-28 | 1988-02-09 | The Boeing Company | System for removing toxic organics and metals from manufacturing wastewater |
DE3633066C2 (de) * | 1986-09-29 | 1993-12-02 | Fraunhofer Ges Forschung | Verfahren zum Entfernen von Arsen aus Prozeßwässern der Glasindustrie |
DE3908491A1 (de) * | 1989-03-15 | 1990-09-20 | Fraunhofer Ges Forschung | Verfahren zur entfernung von arsen und/oder antimon aus loesungen, die arsen und/oder antimon als anionische fluorokomplexe enthalten |
Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2040272A1 (de) * | 1967-09-12 | 1971-03-04 | Dorr Oliver Inc | Verfahren zur Abwasserbehandlung unter Phosphorentfernung |
US3617569A (en) * | 1970-07-31 | 1971-11-02 | Dow Chemical Co | Removal of phosphate from waste water |
US3725265A (en) * | 1971-01-22 | 1973-04-03 | Grace W R & Co | Purification of waste water |
JPS5075562A (el) * | 1973-11-08 | 1975-06-20 | ||
JPS5110028A (ja) * | 1974-07-15 | 1976-01-27 | Kubota Ltd | Idonoki |
JPS5126759A (en) * | 1974-08-30 | 1976-03-05 | Hitachi Plant Eng & Constr Co | Hisoganjuhaisui no shorihoho |
SU389691A1 (ru) * | 1971-04-12 | 1977-08-05 | Уральский Научно-Исследовательский И Проектный Институт Медной Промышленности | Способ очистки кислых сточных вод |
GB1502775A (en) * | 1975-06-30 | 1978-03-01 | Borax Cons Ltd | Removal of arsenic from aqueous effluents |
US4138231A (en) * | 1976-04-09 | 1979-02-06 | Boliden Aktiebolag | Method of wet-cleaning gases containing sulfur dioxide, halogens and arsenic from pyrometallurgical treatment of sulphidic materials |
US4201667A (en) * | 1979-02-09 | 1980-05-06 | Fmc Corporation | Process for removing arsenic from aqueous mediums |
SU859321A1 (ru) * | 1979-08-03 | 1981-08-30 | Центральный научно-исследовательский институт оловянной промышленности | Способ очистки сточных вод от мышь ка |
US4366128A (en) * | 1980-08-22 | 1982-12-28 | Sherritt Gordon Mines Limited | Removal of arsenic from aqueous solutions |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3423309A (en) * | 1968-03-22 | 1969-01-21 | Dorr Oliver Inc | Waste treatment for phosphate removal |
-
1983
- 1983-09-12 SE SE8304858A patent/SE452307B/sv not_active IP Right Cessation
-
1984
- 1984-08-28 MX MX8411273U patent/MX7707E/es unknown
- 1984-08-29 CA CA000462010A patent/CA1253981A/en not_active Expired
- 1984-08-30 ES ES535544A patent/ES535544A0/es active Granted
- 1984-08-30 ZA ZA846790A patent/ZA846790B/xx unknown
- 1984-09-06 GR GR80306A patent/GR80306B/el unknown
- 1984-09-07 EP EP84850259A patent/EP0139622B1/en not_active Expired
- 1984-09-07 DE DE8484850259T patent/DE3468010D1/de not_active Expired
- 1984-09-07 AT AT84850259T patent/ATE31289T1/de not_active IP Right Cessation
- 1984-09-10 BR BR8404502A patent/BR8404502A/pt not_active IP Right Cessation
- 1984-09-11 JP JP59190444A patent/JPS60143893A/ja active Granted
- 1984-09-11 PT PT79186A patent/PT79186B/pt not_active IP Right Cessation
- 1984-09-11 YU YU1569/84A patent/YU43855B/xx unknown
- 1984-09-11 MA MA20448A patent/MA20224A1/fr unknown
- 1984-09-12 US US06/649,712 patent/US4566975A/en not_active Expired - Lifetime
Patent Citations (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2040272A1 (de) * | 1967-09-12 | 1971-03-04 | Dorr Oliver Inc | Verfahren zur Abwasserbehandlung unter Phosphorentfernung |
US3617569A (en) * | 1970-07-31 | 1971-11-02 | Dow Chemical Co | Removal of phosphate from waste water |
US3725265A (en) * | 1971-01-22 | 1973-04-03 | Grace W R & Co | Purification of waste water |
SU389691A1 (ru) * | 1971-04-12 | 1977-08-05 | Уральский Научно-Исследовательский И Проектный Институт Медной Промышленности | Способ очистки кислых сточных вод |
JPS5075562A (el) * | 1973-11-08 | 1975-06-20 | ||
JPS5110028A (ja) * | 1974-07-15 | 1976-01-27 | Kubota Ltd | Idonoki |
JPS5126759A (en) * | 1974-08-30 | 1976-03-05 | Hitachi Plant Eng & Constr Co | Hisoganjuhaisui no shorihoho |
GB1502775A (en) * | 1975-06-30 | 1978-03-01 | Borax Cons Ltd | Removal of arsenic from aqueous effluents |
US4138231A (en) * | 1976-04-09 | 1979-02-06 | Boliden Aktiebolag | Method of wet-cleaning gases containing sulfur dioxide, halogens and arsenic from pyrometallurgical treatment of sulphidic materials |
US4201667A (en) * | 1979-02-09 | 1980-05-06 | Fmc Corporation | Process for removing arsenic from aqueous mediums |
SU859321A1 (ru) * | 1979-08-03 | 1981-08-30 | Центральный научно-исследовательский институт оловянной промышленности | Способ очистки сточных вод от мышь ка |
US4366128A (en) * | 1980-08-22 | 1982-12-28 | Sherritt Gordon Mines Limited | Removal of arsenic from aqueous solutions |
Non-Patent Citations (2)
Title |
---|
Gulledge et al., "Removal of Arsenic from Water by Adsorption on Aluminum and Ferric Hydroxides," JAWWA, Aug. 1973, pp. 548-552. |
Gulledge et al., Removal of Arsenic from Water by Adsorption on Aluminum and Ferric Hydroxides, JAWWA, Aug. 1973, pp. 548 552. * |
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Also Published As
Publication number | Publication date |
---|---|
ZA846790B (en) | 1985-04-24 |
JPH0521637B2 (el) | 1993-03-25 |
PT79186B (en) | 1986-08-14 |
SE8304858D0 (sv) | 1983-09-12 |
EP0139622B1 (en) | 1987-12-09 |
ATE31289T1 (de) | 1987-12-15 |
GR80306B (en) | 1985-01-08 |
YU43855B (en) | 1989-12-31 |
MX7707E (es) | 1990-09-25 |
EP0139622A1 (en) | 1985-05-02 |
ES8603355A1 (es) | 1985-12-16 |
ES535544A0 (es) | 1985-12-16 |
DE3468010D1 (en) | 1988-01-21 |
SE8304858L (sv) | 1985-03-13 |
YU156984A (en) | 1987-06-30 |
PT79186A (en) | 1984-10-01 |
CA1253981A (en) | 1989-05-09 |
JPS60143893A (ja) | 1985-07-30 |
SE452307B (sv) | 1987-11-23 |
MA20224A1 (fr) | 1985-04-01 |
BR8404502A (pt) | 1985-08-06 |
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